Such a tumble dryer emerges from EP 0 477 554 B1, the contents of which is to be fully included in the present document. In this tumble dryer the heat exchanger through which the process air flows, despite the lint filter by which a large part of the lint arising during the drying process is trapped, is increasingly subjected to the effects of lint which the stream of process air carries with it out of a drum with washing to be dried and which, because of its small size, is not trapped in the lint filter. Such lint is deposited with condensing water vapor in the vicinity of the heat exchanger. In such cases the lint remains mainly in the inflow area of the heat exchanger and gradually forms a felt which perceptibly impedes the stream of process air and worsens the heat transfer within the heat exchanger. This can have significant adverse effects on the efficiency of the tumble dryer. A removable grating is provided on an inlet stream side of the heat exchanger, on which the lint is intended to be deposited and which can be taken out relatively easily to remove the lint. After the grating is taken out the lint can be removed by rinsing the grating through with water.
Whereas this provides a thoroughly practical aid for the removal of lint which is deposited directly on the heat exchanger, the problem remains of lint also accumulating in other locations in the duct for the process air between the drum and the heat exchanger. It is especially likely that condensation of moisture, which starts as soon as the process air stream has left the drum, will promote the deposition of lint. Such lint is especially deposited in the deepest part of the duct where the process air must be diverted from a vertically falling direction to a horizontal direction pointing towards the heat exchanger.